ASN number registration: To register an ASN, you can become a member of your local RIR like RIPE/ARIN or find a sponsoring LIR like
freetransit.ch (personal and non profit)
Make the required database objects in your local RIR.
Find upstream providers for your BGP router to connect to: vultr.com, ifog.ch, route48.org, route64.org, freetransit.ch.
Setup a Router: can be a VPS with debian 11 and bird2, mtr-tiny (for troubleshooting later)
Setup a Routinator instance for RPKI cache: do this on a separate vps and not your router vps it will use a lot of cpu power.
Setup DNS resolvers: your choice you can do this on your router with something like Bind9 but it's better to do this on a separate VPS. Configure it so only your prefixes can use it as a resolver!
Setup RDNS: use knotc DNS server if you want to generate automatic forward and reverse records for your future ip prefixes.
Once you get your ASN number talk to your upstream providers to have your upstream configured for you.
Make the required database objects in your local RIR like AS-SET and routes.
Make a peeringdb.com profile page for your new ASN number, some upstreams use this page to configure their routers, make sure your AS-SET and maximum number of prefixes is listed correctly.
Let your PA provider configure RPKI for your allocated PA IPv6 space, sometimes this is done automatically you can check it in your routinator ui.
You are all set to start announcing your IP space to your upstream, if all goes well in birdc you should see established connections with the command "s p a"
Now make the required database objects in your RIR to delegate RDNS for your prefixes to your knotc DNS server or get your prefix delegated by your PA provider.
Configure a Nginx,NTP,DoT/DoH server(I use dnsdist for this), private wireguard vpn server if desired on a separate VPS and connect it to your new BGP router via a wireguard tunnel.
If you have reached this far, good job! You are now a tiny self contained ISP with services like me, you can even host your own VPN and use your own ip space wherever you are even on your smart phone with a wireguard app.
Note on using "free" services
When you start your own AS with "free" BGP upstream providers be sure to support your upstream/transit providers as well whenever you can.
Servers and datatraffic cost real money nothing is truly "free".